title: Biosynthesis and functions of the plant sulfolipid.
abstract: Higher-plant chloroplast membranes are composed primarily of four characteristic lipids, namely monogalactosyldiacylglycerol, digalactosyldiacylglycerol, sulfoquinovosyldiacylglycerol (SQDG), and phosphatidylglycerol. Among them, SQDG is the only sulfur-containing anionic glycerolipid and is the least prevalent component of photosynthetic membrane lipids. SQDG biosynthesis is mostly mediated by UDP-sulfoquinovose synthase (SQD1) and SQDG synthase (SQD2). Recently, another essential gene for SQDG synthesis, UGP3, was identified using transcriptome coexpression analysis and reverse genetics. UGP3 is a novel plastid UDP-glucose pyrophosphorylase that supplies UDP-glucose to SQD1 in plastids. In Arabidopsis, SQDG is dispensable under normal growth conditions but important in certain environments, particularly phosphate-depleted conditions. The function of SQDG under phosphate-limited growth conditions is highly correlated with the regulation of other plant glycerolipid biosyntheses. This review summarizes recent research defining the mechanism for SQDG biosynthesis and its biological function in higher plants, particularly under phosphate-starved conditions.
authors.affiliation: Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259-B65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan. shimojima.m.aa@m.titech.ac.jp
authors.forename: Mie
authors.initials: M
authors.lastname: Shimojima
mesh_terms: D005964:Glucosyltransferases / Q000378:metabolism; D006017:Glycolipids / Q000096:biosynthesis* / Q000502:physiology; D008055:Lipids / Q000096:biosynthesis*; D010944:Plants / Q000378:metabolism*; D014532:Uridine Diphosphate Glucose / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D006017:Glycolipids; D008055:Lipids; C015518:sulfolipids; C013694:sulfoquinovosyl diglyceride; C096386:uridine diphosphate sulfoquinovose; D005964:Glucosyltransferases; C492484:UDP-sulfoquinovose synthase, Chlamydomonas reinhardtii; D014532:Uridine Diphosphate Glucose